Cita APA (7th ed.)
Orr, E. L., & Orr, W. N. (2012). Oregon geology (6th ed.). Oregon State University Press.
Cita Chicago (17th ed.)
Orr, Elizabeth L., i William N. Orr. Oregon Geology. 6th ed. Corvallis: Oregon State University Press, 2012.
Cita MLA (9th ed.)
Orr, Elizabeth L., i William N. Orr. Oregon Geology. 6th ed. Oregon State University Press, 2012.
Atenció: Aquestes cites poden no estar 100% correctes.